Competitive Programming Series — Session 1: The Foundations You Need Before Solving Problems

Competitive programming often looks like a race to write code as fast as possible. But the real secret is simpler: the best competitive programmers are not just faster typists — they are better at choosing the right data structure, the right algorithm, and the right complexity level for the job. Before we jump into recursion, dynamic programming, graphs, or those problems that make your brain do backflips, we need a solid base. This first session is exactly that. Let's begin. 🚀 1. Data Types: What Kind of Data Are You Storing? A data type tells a programming language what kind of value a variable holds and what operations are valid on it. Primitive Data Types The basic building blocks provided by the language itself: Integer — whole numbers: 5 , 100 , -3 Float / Double — decimal values: 3.14 , 99.5 Character — a single symbol: 'A' , 'z' Boolean — true or false User-Defined Data Types When primitive types are not enough, programmers define their own: Structs — group related fields under one name Classes — structs with behaviour (methods) attached Enums — a fixed set of named constants Typedefs / Aliases — rename existing types for clarity A Real-World Example Imagine building a food delivery app: An integer stores the number of items in the cart A float stores the total bill amount A boolean tracks whether the order has been delivered A class represents an entire Order — customer name, address, items, payment status Data types are essentially the labels on your containers. Without them, chaos begins early. 2. Data Structures: How Do You Organise Data? If data types answer what a value is, data structures answer how to organise many values efficiently. This is where competitive programming starts to get interesting. Linear Data Structures Elements arranged one after another, like people queuing at a ticket counter: Arrays — fixed-size, indexed, fast random access Linked Lists — dynamic size, efficient insertions and deletions Stacks — last in, first out (LIFO) Queues